The difference between hot rolled galvanized sheet and cold rolled galvanized sheet
In the regular trading of galvanized sheets, cold-rolled basic galvanization is the main one, and hot-rolled substrates are relatively rare. Then, what is the difference between hot-rolled substrates and cold-rolled substrates galvanized products? Let's make a simple interpretation from the following aspects
Cost
Because there is one less process than the cold-rolled substrate, the production cost of galvanizing the hot-rolled substrate is lower than that of the cold rolling, mainly due to the annealing cost and the cold rolling cost, and the other processes are similar.
Quality & Performance
Because the hot-rolled substrate is only pickled and annealed to remove surface impurities, its surface is relatively rough, the adhesion of the zinc layer is better, and the thickness of the coating is biased toward 140/140g/m2. However, the thickness dimension is not as high as that of cold rolling. Since most of them are thick zinc layers, the thickness of the zinc layer is not uniformly controlled. There is little difference in mechanical properties, and some properties are even better than cold rolling.
Application Field
Hot-rolled base plate galvanized sheet is not as good as cold-rolled base plate because of its dimensional accuracy and surface quality, and the thickness is thicker than cold-rolled galvanized sheet, so it is often used for structural members with low surface requirements but high strength and thickness requirements.
For example, the structural parts of washing machines, refrigerators and other household appliances, automobile internal structural parts, automobile chassis structural parts, passenger car body, roof, highway guardrail, cold-formed steel, etc.
Because the cost of hot-rolled galvanized sheet is low, and as the technology progresses, the thickness of the specifications is getting larger and larger, and the amount of use is gradually increasing.
Grade
Common grades of hot-rolled galvanized sheet are DD51D+Z, HD340LAD+Z, HR340LA, HR420LA, HR550LA, etc.;
The cold-rolled galvanized sheet corresponds to DC51D+Z, HC340LAD+Z, HC340LA, HC420LA, HC550LA, etc.;
There is also a grade that does not specify whether it is cold-rolled or hot-rolled substrate, such as DX51D+Z. Generally, this grade can be considered as hot-rolled galvanized sheet.
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Hot Rolled vs Cold Rolled Steel
钢有多种等级、规格、形状和表面处理——世界钢铁协会列出了3500多种不同等级的钢,每种钢都具有独特的性能。钢的种类繁多,这意味着钢可以广泛用于基础设施、电器、车辆、风力涡轮机和更多的应用领域。
Steel comes in many grades, specifications, shapes, and finishes—the World Steel Association lists over 3,500 different grades of steel, each with unique properties. The various types mean that steel can by widely used in infrastructure, appliances, vehicles, wind turbines, and many more applications.
然而,针对每种应用优化钢的性能不仅仅是改变化学成分。钢材的制造工艺也会对钢材产品产生重大影响——即使等级和规格相同。预制钢产品之间的主要区别之一是热轧钢和冷轧钢之间的区别。
Optimizing steel’s properties for each application goes beyond changing the chemical composition, however. The manufacturing processing of steel can also have a significant impact on steel products—even when the grades and specifications are the same. One key distinction among pre-fabricated steel products is the difference between hot rolled and cold rolled steel.
热轧钢和冷轧钢的主要区别在于工艺。“热轧”是指加热加工,“冷轧”是指在室温或接近室温下进行的工艺。尽管这些技术会影响整体性能和应用,但不应将它们与冶金成分和性能等级相关的钢的正式规格和等级混淆。不同等级和规格的钢可以是热轧或冷轧的——包括基本碳钢和其他合金钢。知道该用哪一种可以帮助避免在原材料上花费过多。它还可以节省额外处理的时间和金钱。了解冷热钢之间的区别对于选择一种钢材是必不可少的。
It’s important to note that the main difference between hot rolled and cold rolled steel is one of process. “Hot rolling” refers to processing done with heat. “Cold rolling” refers to processes done at or near room temperature. Although these techniques affect overall performance and application, they should not be confused with formal specifications and grades of steel, which relate to metallurgical composition and performance ratings. Steels of different grades and specifications can be either hot rolled or cold rolled—including both basic carbon steels and other alloy steels. Knowing which to use can help avoid over-spending on raw materials. It can also save time and money on additional processing. Understanding the differences between hot and cold steel is integral to choosing one over the other.
热轧钢Hot rolled steel
热轧钢是在1700˚F以上的极高温度下进行辊压的钢,这高于大多数钢的再结晶温度。这使得钢更容易成型,从而生产出更容易加工的产品。
为了加工热轧钢,制造商首先从一种称为钢坯的大矩形金属开始。钢坯被加热,然后送去进行预处理,在那里它被压扁成一个大卷。它被保持在高温下,并通过一系列辊子以达到其最终尺寸。白热的钢绞线被高速推过辊子。对于金属板材,轧钢被旋制成卷并冷却。对于其他形式,如棒材或板材,材料是分段包装的。
钢在冷却时会略微收缩。由于热轧钢在加工后冷却,对其最终形状的控制较少,因此不太适合精密应用。热轧钢通常用于对详细尺寸要求不太精确的应用。铁轨和建筑项目通常使用热轧钢材。
Hot rolled steel is steel that has been roll-pressed at very high temperatures—over 1,700˚F, which is above the re-crystallization temperature for most steels. This makes the steel easier to form, and resulting in products that are easier to work with.
To process hot rolled steel, manufacturers first start with a large, rectangular length of metal, called a billet. The billet is heated and then sent for pre-processing, where it is flattened into a large roll. From there, it is kept at a high temperature and run through a series of rollers to achieve its finished dimensions. The white-hot strands of steel are pushed through the rollers at high speeds. For sheet metal, rolled steel is spun into coils and left to cool. For other forms, such as bars or plates, materials are sectioned and packaged.
Steel shrinks slightly as it cools. Since hot rolled steel is cooled after processing, there is less control over its final shape, making it less suitable for precision applications. Hot rolled steel is often used in applications where minutely specific dimensions aren’t crucial. Railroad tracks and construction projects often use hot rolled steel.
热轧钢通常可以通过以下特征来识别:
有鳞的表面——来自极端温度的冷却残留物
棒材和板材产品的边缘和拐角略微圆滑(由于收缩和不太精确的精加工)
轻微的扭曲,冷却可能会导致轻微梯形形状,而不是完美的平方角
Hot rolled steel can often be identified by the following characteristics:
A scaled surface—a remnant of cooling from extreme temperatures
Slightly rounded edges and corners for bar and plate products (due to shrinkage and less precise finishing)
Slight distortions, where cooling may result in slightly trapezoidal forms, as opposed to perfectly squared angles
热轧钢通常比冷轧钢需要的加工少,这使得它便宜得多。因为热轧钢可以在室温下冷却,所以它基本上是正火的——这意味着它没有淬火或加工硬化过程可能产生的内应力。
在尺寸公差不如整体材料强度重要且表面光洁度不是关键问题的情况下,热轧钢是理想的选择。如果表面光洁度有问题,可以通过研磨、喷砂或酸洗去除结垢。
Hot rolled steel typically requires much less processing than cold rolled steel, which makes it a lot cheaper. Because hot rolled steel is allowed to cool at room temperature, it’s essentially normalized—meaning it’s free from internal stresses that can arise from quenching or work-hardening processes.
Hot rolled steel is ideal where dimensional tolerances aren’t as important as overall material strength, and where surface finish isn’t a key concern. Where surface finish is a concern, scaling can be removed by grinding, sand blasting, or acid-bath pickling.
冷轧钢Cold rolled steel
冷轧钢本质上是经过进一步加工的热轧钢。热轧钢冷却后,在室温下重新轧制,以获得更精确的尺寸和更好的表面质量。
Cold rolled steel is essentially hot rolled steel that has been through further processing. Once hot rolled steel has cooled, it is then re-rolled at room temperature to achieve more exact dimensions and better surface qualities.
冷轧钢通常可以通过以下特征来识别:
更好、更精加工的表面,公差更小
光滑的表面,通常摸起来很油腻
条形通常有明确的棱角
管材具有更好的同心均匀性和直线度
Cold rolled steel can often be identified by the following characteristics:
Better, more finished surfaces with closer tolerances
Smooth surfaces that are often oily to the touch
Bars are true and square, and often have well-defined edges and corners
Tubes have better concentric uniformity and straightness
冷轧钢具有比热轧钢更好的表面特性,因此冷轧钢用于技术上要求更精确的应用或美学很重要的应用也就不足为奇了。但由于冷成品的额外加工,它的价格更高。
在物理特性方面,冷轧钢通常比标准热轧钢更硬、更坚固。由于金属在较低温度下成型,钢的硬度、抗张断能力和抗变形能力都因加工硬化而增加。
然而,这些额外的处理也会在材料内产生内应力。如果钢材在切割、打磨或焊接之前没有消除应力,则可能会导致不可预测的翘曲。
With better surface characteristics than hot rolled steel, it’s no surprise that cold rolled steel is often used for more technically precise applications, or where aesthetics are important. But due to the additional processing for cold finished products, they come at a higher price.
In terms of physical characteristics, cold rolled steels are typically harder and stronger than standard hot rolled steels. As the metal is shaped at the lower temperatures, the steel’s hardness, resistance against tension breaking, and resistance against deformation are all increased due to work hardening.
These additional treatments, however, can also create internal stress within the material. This can cause unpredictable warping if the steel is not stress relieved prior to cutting, grinding, or welding.
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Hot-dip galvanizing process characteristics
利用锌对钢铁进行防腐的工艺很多,如:电镀锌工艺,锌层厚度一般控制在5~15μm;吹镀热镀锌工艺(本书专指“吹镀”、下同)的镀锌层较厚,一般在35μm以下;吊镀工艺的镀锌层厚度则在65μm以上,有的产品要求镀锌层厚度甚至高达100μm以上,对于大型钢结构及箱型截面(本书统一为“腔体工件”、下同)钢结构来说,镀锌层厚度则更大一些。
There are many processes that use zinc to prevent corrosion of steel, such as: electro-galvanizing process, the thickness of the zinc layer is generally controlled at 5 ~ 15μm; the blown hot-dip galvanizing process (this book refers to "blow plating", the same below), the galvanized layer is more Thickness, generally less than 35μm; the thickness of the galvanized layer of the hanging plating process is more than 65μm, and some products require the thickness of the galvanized layer to be as high as 100μm or more. For large steel structures and box sections (this book is unified as "cavity workpieces" ", the same below) For steel structures, the thickness of the galvanized layer is larger.
热镀锌工艺的覆盖能力好,镀锌层致密,无有机物夹杂,其腐蚀防护或者说耐腐蚀性能远远高于电镀锌;但是,对于吊镀工艺来讲,镀锌层厚度值有一个较厚的下限值,也就是说,镀锌层太薄了反而不容易做到;对于吹镀工艺来讲,根据型材、管材等的技术指标要求,镀锌层厚度的控制则相对灵活得多。
The hot-dip galvanizing process has good coverage, the galvanized layer is dense, without organic inclusions, and its corrosion protection or corrosion resistance is much higher than that of electro-galvanized; however, for the hanging plating process, the thickness of the galvanized layer has a higher value. The lower limit of thickness, that is to say, the galvanized layer is too thin, but it is not easy to achieve; for the blow plating process, according to the technical index requirements of profiles, pipes, etc., the control of the thickness of the galvanized layer is relatively more flexible .
镀锌层对钢铁的保护作用是双重的,首先,抗渗透性能良好的镀锌层将被保护的钢铁与腐蚀性环境完全隔离,从而彻底消除了钢铁发生腐蚀的一个主要条件,即“电解质”。其次,由于锌的化学活泼性高于钢铁,因而更容易被腐蚀溶解(牺牲阳极原理),一旦镀锌层出现局部损坏,钢材表面外露,锌就成了阳极,先于钢铁发生腐蚀,从而达到了保护钢材的目的。
The protective effect of the galvanized layer on steel is twofold. First, the galvanized layer with good penetration resistance completely isolates the protected steel from the corrosive environment, thereby completely eliminating one of the main conditions for steel corrosion, that is, "electrolyte" . Secondly, because zinc is more chemically active than steel, it is more likely to be corroded and dissolved (the principle of sacrificial anode). Once the galvanized layer is locally damaged and the surface of the steel is exposed, zinc becomes an anode, which corrodes before steel, so as to achieve In order to protect the steel.
在镀锌层电化学保护性、致密性、耐久性、免维护性,镀锌层与钢铁基
体结合力,镀锌层经济性,以及热镀锌工艺对工件形状、尺寸的适应性,生产的高效性等全方面进行比较,热镀锌工艺具有其他金属腐蚀防护工艺无可比拟、得天独厚的优势。
In the electrochemical protection, compactness, durability, maintenance-free of the galvanized layer, the bonding force of the galvanized layer and the steel matrix, the economics of the galvanized layer, and the adaptability of the hot-dip galvanizing process to the shape and size of the workpiece, the production Compared with all aspects such as high efficiency, the hot-dip galvanizing process has the unparalleled and unique advantages of other metal corrosion protection processes.
Introduction to the classification and use of galvanized sheet.
镀锌钢板
镀锌钢板按生产工艺可分为以下几类:
Galvanized steel sheet according to the production process can be divided into the following categories:
1、热镀锌钢板。将钢板浸入熔融锌浴中以将镀锌钢板粘附到表面。目前主要采用连续镀锌工艺生产,即将成卷的钢板连续浸入镀槽中,锌在镀槽中熔化形成镀锌钢板。
1.Hot dip galvanized steel sheet. The steel sheet is immersed in a molten zinc bath to adhere a zinc-plated steel sheet to the surface. At present, it is mainly produced by a continuous galvanizing process, that is, a coiled steel plate is continuously immersed in a plating tank in which zinc is melted to form a galvanized steel sheet.
2. 合金镀锌钢板。这种钢板也是采用热浸法来生产,但是在取出后,立即将其加热到大约500℃,以形成锌和铁的合金涂层。这种镀锌板具有良好的涂层附着力和焊接性。
2.Alloyed galvanized steel sheet. This steel sheet is also produced by hot dip, but immediately after it is taken out, it is heated to about 500 ° C to form an alloy coating of zinc and iron. This galvanized sheet has good adhesion and weldability of the coating.
3.电镀锌钢板。通过电镀生产这种镀锌钢板具有良好的可加工性。但镀层较薄,耐蚀性不如热镀锌板。
3.Electro-galvanized steel plate. The production of such a galvanized steel sheet by electroplating has good workability. However, the coating is thinner and the corrosion resistance is not as good as that of hot dip galvanized sheet.
4.单面电镀和双面差镀锌钢板。单面镀锌钢板,即只在一侧镀锌的产品。在焊接、喷漆、防锈处理和加工方面比双面镀锌板具有更好的适应性。为了克服一侧未镀锌的缺点,有一种在另一侧镀有薄薄一层锌的镀锌板,即双面差镀锌板。
4.Single-sided plating and double-sided differential galvanized steel. Single-sided galvanized steel, that is, a product that is only galvanized on one side. It has better adaptability than double-sided galvanized sheet in welding, painting, anti-rust treatment and processing. In order to overcome the shortcomings of uncoated zinc on one side, there is a galvanized sheet coated with a thin layer of zinc on the other side, that is, a double-sided differential galvanized sheet.
5.合金、复合镀锌钢板。它由锌和其他金属,如铅、锌合金甚至复合镀钢制成。这种钢板具有优良的防锈性能和良好的涂层性能。
5.Alloy, composite galvanized steel sheet. It is made of zinc and other metals such as lead, zinc alloy or even composite plated steel. This steel plate has excellent rust resistance and good coating properties.
除上述五种外,还有彩色镀锌钢板、印刷镀锌钢板、聚氯乙烯层压镀锌钢板等。然而,最常用的仍然是热浸镀锌板。
In addition to the above five types, there are also colored galvanized steel sheets, printed galvanized steel sheets, and polyvinyl chloride laminated galvanized steel sheets. However, the most commonly used ones are still hot dip galvanized sheets.
镀锌钢板又可分为通用型、屋面型、建筑外墙板型、结构型、瓦板型、拉伸型和深冲型镀锌钢板。
Galvanized steel sheets can be further divided into galvanized steel sheets for general use, roofing, exterior panels for buildings, structural, tiled slabs, tensile and deep drawing.
镀锌板广泛应用于汽车工业、建筑业、家具制造、交通运输等行业。
Galvanized sheet is widely used in automobile industry, construction industry, furniture manufacturing, transportation and other industries.
镀锌板用于建筑业:房顶、房顶预制构件、生活阳台控制面板、阳台、书报亭、库房、电动卷帘门、电暖器、降水管路等。
Galvanized sheet is used in the construction industry: roof, roof prefabricated components, living balcony control panel, balcony, book kiosk, warehouse, electric rolling shutter door, electric heater, precipitation pipeline, etc.
镀锌板用于电器产品:冰箱、全自动洗衣机、高压开关柜、空调、微波炉、面包机、打印机、自动售卖机、电扇、吸尘机等。
Galvanized sheet is used in electrical products: refrigerator, automatic washing machine, high voltage switch cabinet, air conditioner, microwave oven heating, bread maker, printer, vending machine, electric fan, vacuum cleaner, etc.
镀锌板用于家装行业:灯罩、衣橱、餐桌、书柜等。
Galvanized sheet is used in home decoration industry: lamp cover, wardrobe, dining table, bookcase,etc.
镀锌板用于运输和制造行业:汽车顶棚、汽车外壳、车箱板、拖拉机、电动车、海运集装箱、货轮舱室板等。
Galvanized sheet is used in transportation and manufacturing industry: Car ceiling, car shell, truck board, tractor, electric vehicle, shipping container, cargo ship compartment board, etc.
镀锌板用于其他方面:传统乐器盒、垃圾桶、广告牌、银行柜台、钟表、医疗器械、摄影器材、计量器等。
Galvanized sheet is used in other aspects: traditional musical instrument case, trash can, billboard, bank counter, clock, medical equipment, photographic equipment, meter, etc.
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What is Success?
In our societies, we use the word success a lot.
And we think we know what it just means, money, status, fame and power.
But take a look at the dictionary, and start to think it thankfully and a lot more complicated
Because success, is in truth, rather more neutral, and less valuated than you tend to assume
It just means doing anything well, excelling at something
And that might compose a lot of different activities.
Running one hundred meters for sure. Selling your rap for a lot of money, Ok
But also stranger less heroic things. Like, listening a lot very attentively to a child or being extremely kind to strangers or filling your mind with interesting ideas in associations, or knowing just when to put an arm around someone when it is too much frozen.
People who are tying fear are also big success stories.
No one can be successful at everything.
Whatever they tell us, it's almost impossible to succeed with career and with family, or with popularity and integrity.
There are always sacrifices.
It's great to be successful.
It is even better to make sure you followed your own distinctive and not necessarily always obvious path to the success that can truly fulfill you
Middle East client visit
On the end of November, 2018, one Middle East clients come to visit our company office----Rogosteel. He have visit China for many times, and a “China Expert”. Before this visit, we have been discuss about order for a long time.
At about 13:00pm, He arrived our office by taxi, and we spend one hour to do further discussion, and show the sample. He is satisfied with our products, and give us the order details to quote. We talked a lot dyring our meeting, make us know better for each other. After this, he bring one piece of our sample to his factory to do some test.
We will do more better during communicate with your customers, and grow together.